Magnetic separator



Feb. 10, 1953 R. H. sTEARNs ETAL MAGNETIC SEPARATOR I 5 Sheets-Sheet lFiled July 24, 1950 m\ wm mw NN l .WMWI lif im Q Q Q fm i if. :..Hm w

@www

Feb. 10, 1953 R. H. sTEARNs ETAL 2,627,976

MAGNETIC sEPARAToR l Filed July 24, 1950 5 Sheets-Sheet 2 iff-9.2

IN V EN TORS.

Feb. 10, 1953 R. H. sTEARNs ETAL MAGNETIC SEPARATOR 5 sheets-sheen sFiled July 24, 1950 l .....mmlullllllllm '413/ lll/ll INVENTORS. .9%.5L'

Fauve/ BY .24am/d' Ellas. 2@ A? Patented Feb. 10, 1953 UNITED STATESPATENT oFF-Ice Biiu s, Milwaukee, Wis., assignors, by direct andir'i'siie assignments; 'of onehalf to said lRoswell Helstveariis andone-half to Roswell N; Stearns,

Fax-Paint; Wis;

Appeaden 3111.39.24, 19150,y serial No. niet@ 6 laims.v

The primary piirs'e of this is vte provide a magnetio separator -vvhiohVis especially" designed for the reeovery of fraaie` salmon, ormagnetite, or other materials er" thlsneal 5 nature, which are usedinthe eleaninenand puri@ tying of coal and the .refery' -ofores andother materials which Vare sibjeted totieatxnent by the heavy-mediaseparatonproe'ess.-

In heavy-lfledlaI Separation a Solution ofy a given specific gi-"aity,vV4consisting of a brepared mixture of magnetic Solids and Water; is de#-livered by suitable meansto a separatori vessel'. The specific g'ravitiiof soliti is ebtaindby the suspension of known quanti-ties 'iilyeoiidferro silicon, or magi-ietite, er si-ii-la'r materialsin the separatoryvessel. The-twoor-Ymo're erals or' materials, which are fth-sproperlyprepared and which itis desi-d-t"Selrt'e are introduced While'Sulorl'leged`y it Y the separatori? chamber. In this processit-,isiin-peiative that the exact specific gravity of theVs'cilutieiibe` mai-'r1- tained at all times, and that substantially nevariation be pe'rmittedfreinA the-desired gravity. It is obvious thatasthe sep terials are removed from the.sbli-itio'nv the ferro silicon oriria etit is* c Y, ,y Y With these iateialsfnitlsif'porti ofthsematerials which 'Produce' thefdesird-sjie'in gravity are constantlyremoved freinthesepa"-v ratory vessel.

This invention sqdesig'rid to prei/idea inegi-- netic separator whichisso -mde'that' it will recover the ferro silieon;v ma'giieti-tev,Vorfotlier 'ineiterial of this nature to 4vareni-arkabl`yliigl'i degreeso that only-a minutefraction ofoneperceiit is ultimately-lost,- andsothatthe recoier'ed {nag-V netic materials can be-returnd to'the*se'pznat'oryV vessel, Vand thus the predeterminedlo' selected'specific vgravity-in the-separatori," chamber can', bejmaint-ainedat a s.iibstantially'r constant value.

When it is considered that the `heavy` edia separation processi'sfredieitly employed in the separation of maten-'alsof highervSpecific gravity' from materials of lower sec gravi ,-as' in lo'iivvgrade ores, for example, and I "tris considered furtherthat the magneticmaterial for produ'e# ing' the desired specific gravity. such vas ferrosilicon and magnetite, are.very"expensve and are used in greatquantities', it Will ,be apparent that the recovery of thismaterialbythe maglnetic separator has to bejapproidmtely perfect in order toelciently and economically conduct the separating process.lru'rthe''r'Yobj(2613's h; therefore, to lroiiide' fortifi* reci ofnon-2" maeneti material and 'a substantial portion of the -li'ciid forreuse. This is accomplished by providing a eliannel in the Sep'arator'y4chamber of the ma'g'netie separator for the overflow of said liquid,said channel being located at the inlet side or the right or far end ofsaid separatory chamber v'vitl intake for the overflow substantiallybelow the level of the liquid rand adjacent theiieniag'netic materialoutlet in said chamb'eiytlie out-'let in 'said channel emptying into areceiving tan-k for return to the circuit Where the liquid is again usedin the mixture. n

When itis considered that the success of the heaify=med`a process liesin the maximum recovery of values, both magnetic and non-magnetic, itwill readily be seen that the all-important function of the magneticseparator is to effect savings in all branches of its operation.

Attention is, therefore, directed to a further object of the intention,vwhich includes the recovery of a substantially greater portion o 'i'thenon'rnagnetic material than would otherwise be possible. This isaccomplished by providing for the channeling ,of the liquid overflow yaSherein described, Wljiih directlyrprevents, to a major degln-ze,y theturbulence near the surface of the lidu'idin thel'separatorychanibercaused by the feed and the action of the' magnetic particles Vinreleasing the non-magneticparticles. Thennes of the non-magneticportion, therefore, cannot noa-t 01T, but are allowed to'v settle and bedischarged Withy the coarse non-magnetic portion, andthufs lWhere valuesare found in said-non- 'i-agneti portion', greater economies in opera-,-doris are' obtained.

Frther' advantages of this invention are obtained the operation off-theseparator. For e aiple, rtheutili zation of this channel for over'-ilotfofeizce'ss liquid enables maintaining a con# stanti` tvaterlevelthe separatory chamber under'v greater yvarialt-ion ofv feed volumes tothe mag"eticAsepar-ator,because of the ability'to discharge -the majorportion of liquid through the channel Without creating detrimentalturbulence and *Water cui'jrei'fits in the separating zone.

@te ...e/ ns Separates. partcula-fly dse which have an overnowadiacentthe upper surface er thehiiqgie, and which are used'for" similarpurposes cannot eiciently maintain aconstatvvater level under Widelyvarying feed con'- dltions, thusreslting in loss of operating'vvate'rlevelylossof'separation of* magnetic from nonmagnetici material, Whichinl turn causes loss of time adzof ,expen'site materials vtotlest'orere# Further objects are to provide a magnetic separator in which atraveling belt is passed through a liquid, in which the materials to beseparated are presented by suitable feed means to the under side of thebelt, and are passed beneath successive magnetic poles of alternatingpolarity but of uniform strength, said belt being drawn along andbeneath a iiat or separating portion and an upwardly slanting ordelivery portion of the magnetic structure, the last or final polehaving extended ngers pointing toward the discharge end of the separatorto thereby facilitate discharge of the magnetic material.

An additional object of this invention is to provide means whereby themagnetic material approaching the discharge portion or zone of thetraveling belt is subjected to a powerful wringing or dewatering action,said dewatering means comprising a roller magnetically actuated,operating in conjunction with said belt conveyor to produce equalpressure on the magnetic material though the load on. said belt variesto thereby cause the water to be squeezed from the material in a uniformand eiective manner under all con-ditions of load.

An embodiment of the invention is shown in the accompanying drawings, inwhich:

Figure 1 is a side elevation with parts broken away and parts in sectionshowing the separator.

Figure 2 is a View from the rear end of Figure l with parts broken awayand with parts in section.

Figure 3 is a detail view partly in section and partly broken awayshowing the discharge portion of the separator and the dewatering orwringing roller,

Figure 4 is an enlarged detail of the last pole structure looking fromthe side.

Figure 5 is a view of the pole shown in Figure 4 looking from the bottomthereof.

Figure 6 is an enlarged view of the dewatering or wringing roller, suchview partly in section and broken away.

Figure 7 is a fragmentary sectional view approximately on the line 'I-lof Figure 6.

Figure 8 is an enlarged sectional detail oi a portion of the front endof the separator showlng the liquid overflow.

Figure 9 is a fragmentary view taken en the line 9 9 of Figure 8.

Referring to the drawings, it will be seen that the separator comprisesa magnet structure indicated generally by the reference character Iwhich is provided with a series of downwardly projecting poles 2 withtheir bottom edges ar ranged in a horizontal or flat line. This portionof the magnet structure will hereinafter be referred to as the ilatportion thereof. The magnet structure also has a series of downwardlyprojecting poles 3 which are arranged in a slantingl manner, the end ofthe series of poles being indicated by the reference character 3 andbeing shown in greater detail in Figures 3, 4, and 5. This end pole 3 isprovided with a plurality of tapered, rearwardly projecting fingers 4which are also upturned, as shown clearly in Figure 4.

The separator is provided with a belt conveyor 5 which is carried by anidler pulley 6 at the intake end and by a driving pulley 'I at thedischarge end. The driving pulley I is driven through reduction gearingand a chain drive from an electric motor 8. The belt is also guided by aguide pulley or small pulley 9 adjacent its bottom stretch. Thisarrangement insures a taut lower stretch of the belt. The belt runs overa wooden guide I0 which has rounded ends and a series of wooden guidesII and I2 and a iinal guide I3.

The separator is provided with a separatory chamber I4 and a dischargechamber I5, which latter receives themagnetic material. The mixedmaterial, consisting of magneticand non-magnetic material in the form ofa slurry, is fed downwardly through the chute or feed pipe I6. This feedpipe extends downwardly below the liquid level in the separatory chamberId and is closed on vall sides except at its extreme lower portion. Thislower portion has an open section I'I immediately below the belt and anupturned portion I8 at its extreme end. The mixture of magnetic andnon-magnetic material is thus fed to the under side of the belt belowthe separating poles 2'. These separating poles 2 are of uniformmagnetic intensity and of alternate polarity. The material is washedthoroughly and the non-magnetic material is shaken loose and washed freeof the magnetic material while the belt passes below the poles 2 andwhile the material is below the liquid level in the separatory chamberIii. The non-magnetic material freely falls downwardly into theseparatory chamber I4 and is discharged through its discharge portionI9, a suitable valve 2d being provided to assist in maintaining theliquid level in the separatory chamber. However, the liquid level ismaintained in the separatory chamber iti primarily by the novelarrangement of liquid discharge means hereinbelow described. This liquiddischarge means consists of a channel 2I which is formed between theforward si-de of the downwardly tapered separatory chamber and a baiiie22. It opens at a point 23 far below the upper liquid level and theliquid passes upwardly through the channel 2l and is discharged over anadjustable plate or dam 24 into the liquid discharge chamber or pipe 25.

ParticularV attention is called to the fact that this discharge of theliquid is so arranged that it prevents turbulence at the surface orliquid level and thus prevents needless turbulence at the point whereseparation occurs. A further and very important feature of this modeofdischarging the liquid is that the fines which often temporarily oaton the surface of the liquid are not swept into the liquid dischargepipe 25. Instead they settle downwardly along with the rest of thenon-magnetic material to the bottom of the separatory chamber I4 and aredischarged through its discharge outlet I9.

The slanting portion of the magnetic structure coacts with the travelingbeltvconveyor and constitutes the conveying or discharge portion asdistinguished from the separating portion. The clinging magneticmaterial is carried upwardly past the poles 3 to the final pole 3 andpasses over a wringing or dewatering roller 25. This dewatering rolleris formed of magnetic material and is drawn upwardly by the flux fromthe adjacent poles of the slanting portion of the magnet structure. Thedetails of the roller construe` tion or roller assembly are shown inFigures 6 and 7. The roller 2S consists of a magnetic cylindricalportion carried by end flanges 21 which are sup-ported from bearings 23carried by a nonrotating shaft 2S. This shaft also carries end membersor crossheads 30 which are joined by means of a transverse rigid strip3I carrying a rubber wiping strip 32 which rubs against the under sideof the roller 25. The ends of the shaft 29 are squared as indicated at33and ride in slots aeemvc 36 formed in end guide members 35 carried bythe side iianges or stationary portion 3B of the separator. The endguides are provided with an overhanging cylindrical portion 31 withinwhich a screw 38 is threaded. Helical compression springs 39 are locatedat opposite ends of the wringing roller. One of the springs is shown inboth Figures 6 and 7. The spring 39 has its upper end bearing againstthe under side of the adjusting screw 38 and its lower end bearingagainst the squared section 33 of the shaft 29. Thus the wringing rolleror magnet-ic dewatering roller is urged downwardly by the spring 39 atopposite ends of its non-rotating shaft 29. However, it is pulledupwardly against the action of the springs into contact with themagnetic material clinging to the under side of the conveyor belt 5. Themagnetic material is indicated by the reference character 4D in Figure 3and it will be seen that the roller 23 bears tightly against suchmagnetic material and serves to wring out or squeeze out excess liquid.Also it is to be noted particularly that the pressure of the rolleragainst the magnetic material is substantially independent of thethickness of the layer of magnetic material clinging to the under sideof the belt.

It is apparent that as the magnetic roller 25 is drawn upwardly that theforce of the springs 39 increases and that the pressure exerted on theclinging magnetic material is the diierence between the upward magneticpull, and the downward force of the springs. Also,l inv view of the factthat the magnetic flux is conducted directly to the magnetic rollerthrough the clinging magnetic material, it is apparent that the iiuxwill cause a heavy pressure to be exerted by the rolle;l for either athin or a thick layer of clinging magnetic material. It is clear,therefore,A that substantially constant pressure will be exerted by themagnetic dewatering roller independently of f the thickness of theclinging magnetic material and that an eihcient and profound dewatering-action will be produced under all conditions.

It is to be noted that a rubber wiper strip 4l is carried by theupwardly extending portion of the tank la and bears against the roller26 and thus serves to assist in conducting the liquid squeezed out ofthe magnetic material 40 back into the separatory chamber or tank l. Themagnetic material, after ithasbeen dewatered, iinally passes beyond thepole 3 and through the lessening magnetic field thereof into a positionof zero :field and is discharged from the belt.

It is to be noted further that the overiiow for the liquid from theseparatory chamber Ill does not disturb the upper surface of the liquidin such separatory chamber as has been previously described. Also theliquid level within the separatory chamber is maintained substantiallyconstant independent of the quantity of slurry fed into the separatorychamber as the liquid can freely flow outwardly through the channel 2lwithout substantially altering the liquid level in the chamber I4.

Further than this, the liquid level in the chamber I4 can be adjusted byadjusting the strip or plate 2d, as shown most clearly in Figures 8 and9. The plate 24 is provided with a plurality of slots l2 through whichthe screws 43 pass, thus permitting lthe plate 24 to be raised orlowered as desired.

It is to be noted further that as the wringing or dewatering roller 2Brises or falls, that the roller assembly as a unit rises and falls andconsequently the rubber wiper strip 32, see Figc ures 6 and 7, ismaintained in wiping engagement with the lower surface of the wringingroller or dewatering roller. Obviously the pressure of the springs 39urging the roller` 26 downwardly can be adjusted by adjusting the screws38.

It will be seen that a novel magnetic separator has been provided bythis invention in which the separating poles ofthe magnet structure arearranged in the same at or horizontal plane and do not thrust thematerial downwardly to varying depths in the liquid in the separatorychamber. instead the poles, as' stated, extend only to exactly the samedepthat the separating portion of the mag-net structure. Further,turbulence of the liquid at this point is substantially avoided by thenovel manner in which the liquid is withdrawn from the separatorychamber i4.

It will be seen further that the dewatering or wringing roller exertsy asubstantially: uniform pressure on the magneticl material' clingingtothe under side of the belt and producesa powerful and uniformdewatering action independently of the thickness of such material.

Although this invention has been describedv in considerable detail, itis to be' understood that such description is intended as illustrativerather than limiting, as the invention maybe variously embodied and isto be interpreted asl claimed.

We claim:

l. A magnetic separator for separating magnetic and non-magneticmaterial in a submerged state, comprising feeding means for saidmaterial, a liquid containing separatory chamber, a discharge tank, amagnet structure having a iiat section and an angular section, ak beltconveyor arranged to travel below said agt and angular sections, saidsections of' said magnetic structure having a series of magnetic fieldsconstituting, respectively, separating and conveying zones for saidmaterial, said' flat,` section having poles of alternate polarity andsaid nat section having its poles submerged in the liquid in saidseparatory chamber and being adapted to wash the material clinging tothe under sideof said conveyor belt and to discharge the non-magneticportion of such material, the magneticv elds of said angular sectioncausing the conveying of the magnetic portion by said belt conveyor tothe far end ci said magnet, structure Where said material is dewateredby passing. between a magnetized ferro-y magnetic roller and'saidconveyor belt, said roller being inductively magnetized by flux linesfrom the end poles passing through the ferro-magnetic roller, saidroller being actuated by the magnet structure to move in an upwarddirection, and counteracting springs controlling the pressure or squeezeon said material, said springs being adjustable to control the amount ofwater being removed from the magnetic material, and said materialthereafter passing to a position of Zero ux intensity thereby allowingsaid magnetic portion to be freely and automatically discharged intosaid discharge tank.

2. A magnetic separator for separating a mixed slurry of magnetic andnon-magnetic material in a submerged state comprising a liquidcontaining separatory chamber, a discharge chamber, a magnet structurehaving a iiat section and an angular section, a belt conveyor coactingwith said magnet structure for separating and conveying the separatedmagnetic portion to the discharge chamber, said separatory vessel havingan opening therein for the passage of non-magnetic material therefrom, adewatering ferromagnetic roller movably mounted and inductivelyadattarel magnetized by said magnet structure and being drawn upwardlythereby towards said belt conveyor, and means comprising adjustablymounted compression springs for maintaining constant pressure on saidmagnetic material between said belt conveyor and said roller as the loadof magnetic material varies.

3. A magnetic separator for separating a mixed slurry of magnetic andnon-magnetic material in a submerged state comprising a liquidcontaining separatory chamber, a discharge chamber, a belt conveyorarranged to travel across said chambers. a magnet structure cooperatingwith said belt conveyor and having a at and an angular section andhaving a plurality of poles in each section, the poles of said atsection being submerged in the liquid in said separatory chamber andbeing of alternate polarity to agitate said material and effect therelease of the non-magnetic material while in the separatory chamber, d

the angular section of said magnet structure having magnetic fieldsarranged to sustain magnetic material in contact with said belt conveyoras it moves towards said discharge tank, a movably mounted inductivelymagnetized dewatering roller arranged to be drawn upwardly by magneticattraction towards said belt conveyor and to vary its distance therefromcorresponding with the load of magnetic material carried by said beltand to provide a predetermined uniform dewatering under varying loadconditions.

4. A magnetic separator for separating a mixed slurry of magnetic andnon-magnetic material in a submerged state, said magnetic separatorcomprising a magnet structure having a submerged separating zone and azone for carrying away the magnetic material, a belt conveyor arrangedto travel beneath said magnet structure, feeding means for feeding saidslurry to said belt in said separating zone, an inductively magnetizeddewatering roller for removing a predetermined amount of the surplusliquid from the magnetic material while the magnetic material is beingconveyed to the discharge end of the magnet structure, said dewateringroller .being mounted near the discharge end and subject to theiniiuence of said magnet structure to produce an upward squeezemovement, and means for causing the automatic discharge of magneticmaterial from said belt conveyor after said belt conveyor has passedsaid magnet structure.

5. A magnetic separator for use in a closed circuit in which a uniformbalance of all the elements circulated therein must be maintained foreconomic and continuous operation, said mag'` netic separator beingarranged for separating a mixed slurry of magnetic and non-magneticmaterial and comprising a magnet structure, a separatory chamber and adischarge chamber, a belt conveyor arranged te travel beneath saidmagnet structure and across said chambers, means for feeding said slurryto the under side of said belt in said separatory chamber, said`separato'ry chamber having a discharge channel for the liquid openingat a point below the liquid level and adjacent the lower portion of saidseparatory chamber to thereby cause decanting of the liquid withoutcausing either turbulence or a transverse flow at the level of saidliquid.

6. A magnetic separator for use in a closed circuit and arranged toseparate a mixed slurry of magnetic and non-magnetic material,dewatering means for dewatering the magnetic material, means forrecovering the coarse non-magnetic material and a substantial portion ofthe nonmagnetic lines and for clarifying the discharged liquid to permitits return for reuse in said circuit, said last recited means includinga separatory chamber having a control outlet for the nonmagneticmaterial, said separatory chamber having a submerged overiiow channel toprevent the loss of fines due to turbulence in the upper portion of theseparatory chamber, said overflow channel having its intake opening at apoint a substantial distance below the liquid level in said separatorychamber to prevent a transverse flow at the surface of the liquid tothereby prevent sweeping of the lines from said separatory charnber andhaving an outlet opening with adjustable means for controlling the levelof liquid in said separatory chamber to thereby decant the liquid whilethe non-magnetic nes in said separatory chamber settle and pass into theoutlet for the non-magnetic material.

ROSWELL H. LSTEARNS. HAROLD W. BUUS.

REFERENCES CTED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

